Emergency aircraft system

ABSTRACT

A turbojet aircraft has a fuselage pod in which all fuel is stored for engines also linked to the pod. The pod and engines can be jettisoned in flight to improve aircraft performance in the event of a forced landing.

This invention relates generally to aircraft systems to faciliatecontinued flight in the event of emergencies, and deals moreparticularly with an aircraft capable of power off emergency flightwherein the engines and fuel can be conveniently jettisoned so that theaircraft is capable of continued flight in an emergency flight mode.

In accordance with the presently preferred embodiment of the presentinvention a turbojet aircraft has a fuselage with cockpit and passengercompartments in a primary fuselage structure, and wings are carried bythis primary fuselage structure as is the empennage. The engines aredetachably secured to the underside of the wings and to a lower fuselagepod structure that cooperates with the main fuselage structure to definea streamlined fuselage shape well suited for normal powered flight. Theinterface between the fuselage and pod includes at least four releasableconnecting or coupling structures such that the pod and engine nacellescan be released in flight. The main fuselage structure is capable ofpower off emergency flight after the pod and engines have beenjettisoned. Fuel is carried in individual fuel tanks arranged in serieswithin the fuselage pod and means is provided for isolating eachindividual tank in the event of an emergency. Fire extinguishing meansis provided within each individual tank compartment or cage and may beactuated automatically or manually in the event of fire, with each tankalso being individually isolated as a result of fuel tank shut-offvalves provided between adjacent tanks.

Means is provided for assuring control of the aircraft during power offemergency flight operations. Means is provided for storing compressedair in the main fuselage portion, during normal flight, by compressorair bleed from the jet engines. This air pressure source is availablefor operating control surfaces for power-off flight. Electrical power isprovided in the main fuselage structure from a conventional battery alsoprovided in the fuselage. Release of the fuselage pod can beaccomplished from the cockpit by mechanical means, with coupling meansprovided between the fuselage and pod. A fuselage mounted housingdefines a rearwardly open socket and the fuselage pod defines aforwardly projecting tapered lug that is receivable in the socket. Arotatably mounted latch or lever is provided on the housing and ismovable from a latched position where the bracket is secured to thehousing to a released position where the bracket is free to moverearwardly relative the housing. Thus, in the event of an emergency, andwhen the aircraft assumes a nose down attitude spoilers or the like inthe wing maybe utilized to the slow the aircraft down in order tofaciliate separation of the fuselage pod and engines from the aircraft.The relatively heavy fuel filled fuselage pod and associated engineswill fall away from the aircraft as a result of which the pilot willhave a very light weight aircraft well adapted for power off emergencyflight.

FIG. 1 is an elevational view of an aircraft constructed in accordancewith the present invention.

FIG. 2 is a top plan view of the right hand portion of the aircraftshown in FIG. 1, the left-hand portion being similar thereto.

FIG. 3 is a front elevational view of the aircraft illustrated in FIGS.1 and 2.

FIG. 4 is a horizontal sectional view taken generally on the line 4--4of FIG. 1.

FIG. 5 is a sectional view taken generally on the line 5--5 of FIG. 3.

FIG. 6 is a section view taken generally on the line 6--6 of FIG. 4.

FIG. 7 is a view taken generally on the line 7--7 of FIG. 5 illustratingthe housing portion of the fuselage mounted mechanical coupling meansbetween the wing and engine or engine nacells.

FIG. 8 is a sectional view taken generally on the line 8--8 of FIG. 7.

FIG. 9 is a detailed view of the crank arm provided to assure latchingof the housing and bracket members of FIG. 5.

FIG. 10 is a view of the bracket illustrated in FIG. 5.

FIG. 11 is a side elevational view of this bracket as it appears in FIG.5.

FIG. 12 is a detailed sectional view through the fuel bladder materialshowing its composite construction.

FIG. 13 is a view similar to FIG. 5 but showing an alternativeembodiment for the coupling means.

Present day turbojet aircraft equipped to carry passengers and/or cargonecessarily include relatively heavy engines, and generally requirerather large fuel loads for these engines. When an emergency situationarises in flight that cannot be corrected by the crew the plane will flyonly poorly with this weight of engines and fuel causing present dayaircraft to crash unnecessarily at relatively high speeds and in remotelocations not suited to such crash landings.

The system disclosed herein will enable the crew to release the relativeheavy engines and associated fuel from the aircraft while it is stillflyable, and give the pilot time to land the lightened aircraftstructure that results in a free flight or power-off emergency mode ofoperation. When the pilot is able to release the engines and fuel fromhis aircraft the loss of weight will give the aircraft additional liftso as to permit gliding greater distances from the point at which theemergency arises, and will also permit the aircraft to land at greatlyreduced landing speeds.

Considering first the embodiment illustrated in FIG. 1, an aircraft isshown having a main fuselage portion 10 to which is attached wings 12and empennage or tail section 14. The fuselage 10 includes a cockpitportion 10a and passenger compartment 10b and it is a feature of thepresent invention that this main fuselage portion also includes theaircraft's battery 16 and a source or storage compartment for compressedair 18. As best shown in FIG. 2 symmetrically arranged wings 12, 12 areprovided one on either side of the fuselage 10 and each wing includesconventional control surfaces in the form of ailerons 12a and landingflaps 12b, 12c. In addition, spoilers 12d may be provided for turning atspeeds where the ailerons 12a are less efficient, and in addition thespoilers 12d serve to decelerate the aircraft for reasons to bediscussed in greater detail hereinafter. Not shown, but also within thescope of the present invention the wing 12 also includes leading edgeslots. Finally, a retractable main gear assembly 20 is provided in theunderside of each wing. FIG. 2 illustrating the gear in its retractedcondition and FIG. 1 illustrates the main gear 20 in its extendedposition. A nose gear 22 may be provided but it is noted that the nosegear is not located in the main fuselage portion 10, but rather islocated in an elongated fuselage pod 24 to be described.

As best shown in FIG. 3 the fuselage pod 24 is connected to and normallypermanently assembled with the main fuselage 10 to cooperate therewithand define a streamline fuselage shape for normal flight. The fuselage10 and pod 24 define an interface or surface 26 therebetween and FIG. 4illustrates in plan view the configuration for the fuselage pod 24 atthis interface. As there shown four connections or couplings 28, 28 areprovided to secure the lower fuselage pod 24 to the main fuselage 10.One such coupling means is illustrated in greater detail in FIG. 5,being the coupling provided between one engine nacelle 30 and the wing12.

In the aircraft shown two engines 30, 30 are provided on stub wings 32,32 each of which stub wings serves to permanently connect the enginenacelle to the fuselage pod 24 and to carry fuel lines to the engine. Asshown in FIG. 5 each engine or nacelle 30 is also connected to the wingstructure 12 by mechanical coupling means, indicated generally at 28 inthis view. In accordance with the present invention each mechanicalcoupling means includes a wing mounted housing member 34 defining arearwardly open tapered socket 34a which socket is adapted to receive alug 36a integrally formed in a bracket 36. The bracket 36 is permanentlysecured to the engine nacelle, as indicated generally at 36b. Arotatably mounted latch/lever 38 is provided to secure the bracket 36 inassembled or coupled relationship to the housing 34 and this lever/latchis adapted to pivot on shaft 40 so as to permit the engine nacelle to bedisconnected from the wing. Rotating lever/latch 38 from the positionshown, where it serves to secure bracket 36 to housing 34, to a releasedposition (not shown) is accomplished by push rod member 42. Member 42may be operated by a fluid actuator from the cockpit, or alternativelyand/or redundantly manual actuation of the lever/latch 38 may beaccomplished from the cockpit through a mechanical push rod linkage.

Similar mechanical coupling means 28, 28 are provided to secure thefuselage pod 24 to the main fuselage structure 10 and each of thesecoupling means comprises a fuselage mounted housing defining arearwardly open socket adapted to receive a bracket lug such as thatreferred to previously with reference to FIG. 5. The lug portion of thebracket is preferably tapered as illustrated in FIGS. 9 and 10 with afive degree taper being provided on at least the top side of the lug anda lesser taper of approximately two degrees on the lower face of thelug. As shown in FIG. 10 the lower portion of bracket 36 is adapted toreceive screws for securing the bracket to the engine housing or nacelle30. Lug portion 38a is shaped so as to having a generally rectangularconfiguration adapted to be received in the socket complementary shapeddefining portion 34a of the housing shown in FIGS. 7 and 8. This housingis provided in the fuselage 10 or wing 12 and each of the brackets 36are provided on either the fuselage pod 24 or engine nacelle 30. FIG. 9shows the latch/lever 38 with its pivot shaft 40 and free end portionadapted for connection to the actuating linkage or mechanism asdescribed previously. End portion 38a of latch 38 is adapted to engagethe rear face of bracket 36 as shown at 36a to secure the bracket inplace in its associated housing 34.

FIG. 13 shows an alternative coupling means 128 for securing an enginenacelle 130 to the aircraft structure, in this case to wing structure112. A wing mounted housing 134 defines a rearwardly open socket 134athat receives the lug 136a of bracket 136. Rotatable latch 138 providesthe latch to hold these members in the assembled relationship shown. Aforwardly projecting pin 140 is threaded into the bracket 136 andextends through an aligned opening in the engine nacelle frame 136b. Theforward end of pin 140 defines a tapered nose 140a which fits into asocket defined for it in block 142. This block is permanently providedin wing 112, and cooperates with the pin 140 to help support the enginenacelle in normal flight. When jettisoned this nacelle 130 will separatefrom the wing just as described above with reference to nacelle 30 inFIG. 5.

Turning now to a more detailed description of the fuel systemincorporated in the fuselage pod 24, FIG. 6 illustrates three adjacentindividual fuel tanks and each of these fuel tanks comprises acollapsible bladder 44, which bladder is supported in a cage structure46 that is specifically designed for this purpose. The cage 46 mayinclude a lower wall having a drain opening 46a such that any leakdeveloped in the bladder 44 will permit excess fuel to drain overboard.In such event fuel shut-off valves 50 provided between adjacent fueltanks as shown allow the crew to isolate any fuel tank where any suchleak develops. These valves are preferably mechanically opearable in theevent of emergency.

A further feature of the present invention is provision of fireextinguishing discharge nozzles 52 in each fuel tank cage whichdischarge nozzles are operated under the control of a fire extinguishingcontrol circuit that includes temperature sensors or smoke detectors ofthe type indicated generally at 54 in each of these individual fuel tankcages. The control circuitry for the fire extinguishing system includesprovision within the cockpit for manual release of the fireextinguishing agent in the event of malfunction in the detection systemof the automatic detection system. It will be apparent from FIG. 4 thatthe individual fuel tanks are connected in at least two strings orseries associated with each of the two engines. Fuel shut-off valves arelocated between adjacent fuel tanks in each string.

FIG. 12 shows, in cross section, the composite structure of bladder 44.The inside layer, or layers, 44a are of elastomeric material such asneoprene or the like. The outermost layer 44b is of flexible stainlesssteel mesh with quarter inch spacing between the wires. FIG. 12 alsoshows another layer 44b of stainless steel mesh sandwiched between thelayers 44c, 44c of fire retardant material.

Finally, and still with reference to the fuel system, the cage structure46 is preferably fabricated from aluminum so that the cage structurewill not penetrate the stainless steel mesh reinforced fuel bladder inthe event of a crash landing or the like. Thus, the cage structure isyieldable to protect the many individual fuel tanks. Each tank iscollapsible so that as fuel is used in flight inert air will fill thespace between the cage and the bladder. This reduces the chance ofexplosion and fire normally associated with partially filled fuel tankson present day aircraft. The many small fuel tanks also helps to reducethe hazard of explosion such as is likely to be presented when a largefuel tank develops an explosive mixture due to the large confined spacein a partially full tank.

Still with reference to FIG. 4 the controls for each of the two nacellemounted engines are provided in the cockpit as indicated generally at100. The shut-off valves provided between each of the individual fueltanks 50, 50 are also controlled from the cockpit as indicated generallyat 102. Finally, the controls for jettisoning the fuselage pod andengines also includes provision for actuating these mechanical couplingmeans from the cockpit as indicated generally at 104 in FIG. 4.

As best shown in FIG. 3 the two engine nacelles 30, 30 are supportedboth from the fuselage pod 24 by stub wings 32, and also are supportedby the coupling means 28, 28 provided for this purpose in verticallyextending struts extending between the underside of the wings 12 and theengine nacelles 30.

If an emergency arises in flight that the crew cannot control so as topermit continuing the flight to a suitable landing at a suitableairport, the crew can isolate the fuselage from the fuel and engines(whether or not the emergency is related to these systems). Afterjettisoning the fuselage pod 24 and engines 30, 30 the pilot can controlhis aircraft even at very low airspeeds. His glide angle will alsoimprove due to the reduction in weight achieved. If fuel is carried inthe wings this can be conventionally dumped also. However, I prefer tocarry all fuel in the pod 24. On landing the nose gear is gone but theweight distribution will allow the pilot to touch down in a nose highattitude that allows for use of tail skid 60 to provide support for theaircraft on the ground. This feature faciliates evacuation of theaircraft through a rear door (not shown) or doors which are closer tothe ground than would be the case normally.

In an emergency immediately after take off, when the pilot may not havetime to jettison the pod and the engines as outlined in the precedingparagraph, the present invention provides another alternative. In such acase the pilot can simply shut off all fuel valves from the cockpit assuggested at 102 in FIG. 4.

I claim:
 1. An aircraft capable of power off emergency flight andcomprising(a) a fuselage having a cockpit, a compartment for passengersand cargo, and fluid pressure storage means in said fuselage, (b) wingsattached at inner ends to said fuselage, said wings having controlsurfaces provided thereon, and said control surfaces including aircraftdecelerating devices, (c) a lower fuselage pod structure cooperatingwith said fuselage to define a streamlined fuselage shape for normalflight, said fuselage and fuselage pod defining an interfacetherebetween, (d) a plurality of individual fuel tanks in said lowerfuselage pod, each fuel tank having a fuel shut-off valve, and means forcontrolling said fuel shut-off valves from the cockpit, (e) at least twoaircraft engines mounted to said fuselage pod structure, fuel linesbetween said engines and said fuel tanks, engine controls provided insaid cockpit, means connecting said engines to said wings, enginecontrol lines for interconnecting said cockpit engine controls with saidengines, and coupling means for said engine control lines, said couplingmeans provided adjacent said means connecting said engines to saidwings, (f) means connecting said fuselage pod to said fuselage, andmeans for disconnecting both said connecting means at the cockpit, (g)at least one engine having an engine accessory capable of pressurizing afluid, and fluid conduit means connecting said accessory with said fluidpressure storage means in said fuselage, and coupling means for saidfluid conduit means, said coupling means provided adjacent the interfacebetween said fuselage and said fuselage pod structure.
 2. The apparatusof claim 1 wherein said means connecting said fuselage pod to saidfuselage comprises at least two mechanical coupling means, each couplingmeans comprising a fuselage mounted housing defining a rearwardly opensocket, a pod mounted bracket defining a forwardly projecting taperedlug portion adapted to be received in said socket, and a rotatablymounted latch/lever provided in said housing and movable from a latchedposition wherein said bracket is secured to said housing and a releasedposition wherein said bracket is free to move rearwardly relative saidhousing, all of said latch/levers being operable remotely from theaircraft cockpit.
 3. The apparatus of claim 1 wherein each saidindividual fuel tank comprises a collapsible bladder, and a support cagefor the bladder such that the bladder is supported when full of fuel,said bladder being resiliently deformable so as to collapse as the fuelis withdrawn.
 4. The apparatus of claim 3 further characterized by afire extinguishing system for said fuselage pod, said system includingsensors for each fuel tank cage, fire extinguishing agent dischargenozzles for each cage, and means for controlling the discharge of suchagent in response to the condition of said sensors.
 5. The apparatus ofclaim 1 wherein at least some of said individual fuel tanks are seriesconnected, fuel shut-off valves being located between adjacent fueltanks so serially connected.
 6. The apparatus of claim 1 furthercharacterized by horizontally oriented stub wings connecting saidengines to said fuselage pod, and vertically oriented struts connectingsaid engines to said wing.
 7. The apparatus of claim 6 furthercharacterized by connecting means in said vertically oriented struts forreleasably securing said engines to said wings, said connecting meanscomprising mechanical coupling means, each coupling means comprising awing mounted housing defining a rearwardly open socket, a engine mountedbracket defining a forwardly projecting tapered lug portion adapted tobe received in said socket, and a rotatably mounted latch/lever providedin said housing and movable from a latched position wherein said bracketis secured to said housing and a released position wherein said bracketis free to move rearwardly relative said housing, all of saidlatch/levers being operable remotely from the aircraft cockpit.
 8. Theapparatus of claim 7 wherein said means connecting said fuselage pod tosaid fuselage comprises at least two mechanical coupling means, eachcoupling means comprising a fuselage mounted housing defining arearwardly open socket, a pod mounted bracket defining a forwardlyprojecting tapered lug portion adapted to be received in said socket,and a rotatably mounted latch/lever provided in said housing and movablefrom a latched position wherein said bracket is secured to said housingand a released position wherein said bracket is free to move rearwardlyrelative said housing, all of said latch/levers being operable remotelyfrom the aircraft cockpit.
 9. The apparatus of claim 8 wherein each saidindividual fuel tank comprises a collapsible bladder, and a support cagefor the bladder such that the bladder is supported when full of fuel,said bladder being resiliently deformable so as to collapse as the fuelis withdrawn.
 10. The apparatus of claim 9 further characterized by afire extinguishing system for said fuselage pod, said system includingsensors for each fuel tank cage, fire extinguishing agent dischargenozzles for each cage, and means for controlling the discharge of suchagent in response to the condition of said sensors.